1. Field of the Invention
The present invention relates to a fluid dynamic bearing device for rotatably supporting a shaft member by means of a dynamic pressure effect of a lubricating fluid generated in a bearing gap.
2. Description of Related Art
By virtue of its high rotational precision and silence, a fluid dynamic bearing device can be suitably used in a small motor such as a spindle motor for an information apparatus such as a magnetic disk drive like an HDD, an optical disk drive for a CD-ROM, CD-R/RW, DVD-ROM/RAM or the like, or a magneto-optical disk drive for an MD, MO or the like, as a polygon scanner motor of a laser beam printer (LBP), as a motor for a projector color wheel, or as a fan motor used in a cooling fan of an electrical apparatus or the like.
For example, a fluid dynamic bearing device disclosed in Patent Document 1 includes a shaft member having a shaft portion and a flange portion, a bearing sleeve made of sintered metal and having a shaft portion inserted along an inner periphery thereof, and a housing which holds the bearing sleeve along the inner periphery thereof. In the end surface of the bearing sleeve, there is formed the thrust dynamic pressure generating portion for generating a dynamic pressure effect in a lubricating fluid in a thrust bearing gap which is formed between the end surface of the bearing sleeve and the end surface of the flange portion.
Patent Document 1: JP 2003-239951 A